Circuit arrangement for high-frequency sending stations



til 12 1927. AP M. OSNOS CIRCUIT ARRANGEMENT FOR HIGH FREQUENCY SENDINGSTATIONS Filed Feb. 17, 1923 Swuemtoz MENDEL O5N05 Patented Apr. 12,1927 v UNITED .oFFrc:E:..

TELE'GZRAPHIE M; GERMANY.

B21 H. HALLIESGHES; OF BERLIN, GERMANY, A

CORPORATION OF CIRCUIT ARRANGEMENT FOB,'HIGH-FZREQUENCY'SENDINGSTATIONSY Application filedTebruary 17,1923,1Serial No. 619,739, and in:Germany-February 18," 1922;

Thepresent invention is a further improvement on the arrangementdescribed inmy application Serial No. 609,215 filed December-27, 1922.

In thedrawing+-- D Fin- 1 is a diagrammatic representation of a, circuitarrangement embodying; the invention described in said application, and

Figs. 2 to 5 inclusive are diagrammatic representations of circuit:arrangements of various forms embodyingthe presentinvention.

In 1 accordancewith said application, the generator is-connected inparallel with an element a so-called trap comprising a capacity (,lInzdetermi-nin'g; the optimum properties of this trap, particularly itscapacity; thefollowing; conditions must be observed. First, theoperation-of. produc ing; oscillations of the'basic frequency mustproceed in themost favorable manner, for example, the value' of theterminal potential of the: generator must-:not under any conditions varymateriallylfrom the idle running value; also as far: as possible thedynamo .urustisupply onlywatt'current; and also the operation: must:beas stable as possible etc. Second, for the purpose ofideveloping thestrongest: possible; harmonic of the desiredefrequency iti is necessarythat the oscillatingg-circuit as a whole, constitute either a-tuned :orslightly capacitive shortcircuit for: 'thedesired harmonic,disregardinn; ohmic losses but that:.it: constitute an essentiallyinductive reactance for the other harmonica .or if it' constitutes acapacitive reactance for-certain gother. harmonics, this mustbesolargethat no considerable oscillations of' undesired frequency will beQ'GllGl'fltGClay Third, as far as. possible the machine mustl beprotected" from all harmonics operatinge waves as well as others.

The attainment" of-the second condition is first of all dependent on thevalue ofithat part of the station which:v comprises the above-mentionedcapacity C the self-i11- duction ofdhogenerator andpossibly a further'self induction connected in: parallel 5 with the-generator;- 1

These. three requirements are not always in: perfect i agreement r witheach other. For

example if the saidcondenser comprisedlin the trap- -which, fast-abovestated, forms part of the tuning apparatuswhich determines the"development of the necessary over waves-is dimensioned for the purposeof satisfyingithe second require1nent;.then it may happen'that thefulfillment of the other requirements will be i very difficultorimpossible.v In: order toobviate this clifficulty in layingout-thesending-station,- in accordance with the present invention; afurthermargin of safety is introduced by providing-5a tuning; devicewhich serves to determine the development of the'desi-red harmonic andwhich is-Tseparatefrom the trap (which is arranged in parallel with thegenerator; Preferably, this tuning element is-composed ofa capacityandan inductance provided in) p arallel with each otherand is arrangedin series with an :iron corechoke coil. I

The -fo -i-'egoin will be" more fully er; plained by means of thecircuit arrangement shownrin hlioyl; Inthis-figure, g is'the highfrequency generator; G and the inductance of the generatoir is-t-hetrap, L the iron core choke-coil, C awning condenser,- L a tuninginductance which. or a part of which'servesalso as a conpling; with theantennacircuit, A the -antenna and-L the extension coil...

The following should be: observed Y in determining the values of theseparate: elements of-the station As faras the basic frequency isconcerned, the current of this-frequency, as well as all others, passingthrough the condenser is leadingiwith respect-to its-terminal potential. Then the branch L, C L must bewso tuned that its primary;currentof basic frequency is .-laggin ','because only in thiscase can wesatisfy the-first requirement for the basic frequency. If, forinstance;the-leading: component @of, the basic frequency. at the condenser C isexactly equal to the lagging component of the basic frequency in theloading branch L C L then' the-generator is freed from thewattlesscurrent and must supply only the minimum of current which a is anecessary for; covering the losses and theoperating wattless currentout-- part. If, on the-other hand, the leadingwon:

denser current exceeds the lagging current components of the loadingbranch so that the generator must supply a leading current, no matter tohow slight a degree, then the value of the terminal potential of thegen- .erator may be made at all times equal to the idle runningpotential.

It will be seen therefore, that, for the purpose of satisfying the firstrequirement the condenser must have such a value that its capacitivereactance is near the inductive reactance of the loading branch L C Lfor the basic frequency and preferably is equal thereto or slightlysmaller.

If, on the other hand, it is desired to determine the value of thecondenser G which would satisfy the second requirement then, as moreexhaustive study of the problem has shown, this mustbe accomplished bytuning the closed circuit comprising the capacity C, and theself-induction L of the generator 9 connected in parallel with thecapacity C, for a frequency which is lower than the desired operatingfrequency, but higher than the next lowest frequency existing in thestation. However, if it is attempted to accomplish this, the capacity ofthe condenser C becomes so small that the third requirement cannot befully satisfied. With respect to the harmonics which are lower than theoperating frequency, the inductive reactance of the generator 9 will besmaller than the capacitive reactance of the condenser C so that itcannot serve satisfactorily as a trap, i. e. as a protection for thegenerator. Furthermore, the value obtained will be lower than isdesirable for satisfying the first condition. 1

In order to obviate this difiiculty, in accordance with the presentinvention the condenser C is given so high a value that it will besatisfactory for the first and third requirements. However, with respectto the second requirement, the condenser C which now operatessatisfactorily as a trap is no longer used as a means for developing thedesired harmonic. The development of the desired operating harmonic iscontrolled by a tuning device which is separate from the trap and whichmay be connected in the loading branch in circuit with the iron corechoke coil.

In Fig. 2 the tuning device in question is composed of a capacity C, anda self-induction L whereas the condenser G, is of sufficiently largedimensions to serve as a protection for the generator 9 against allharmonies.

The aggregate reactance of the tuning element (1,, L has a slightlyinductive character for the basic frequency so that the loading branchmay easily be made inductive for this frequency. On the other hand, thewhole circuit which has a general multi wave character may now be tunedas a short circuit or as a low capacitive reactance for the desiredharmonic.

The present improvement may be applied to all of the circuits describedin my earlier application.

Thus, for instance, from the circuit shown in Fig. i of said applicationwe may obtain the circuit shown in Fig. 3 of the accompanying drawings.In this figure also the said tuning element L C is provided in theloading branch in series with the iron core choke coil L The loadingbranch may in this case be so dimensioned as to have a capacitivecharacter for the basic frequency when the coil L which, as shown, mayhe an iron core choke coil, is so dimensioned that, as far as the basicfrequency is concerned, its lagging current covers entirely or partiallythe leading current of the condenser C and the loading branch or evenexceeds it.

In a similar manner as disclosed in said application, under certaincircumstances instead of using the tuning inductance L for coupling withthe antenna, another inductance comprised in the oscillating circuit andin which the desired operating wave is strongly developed may be used,e. a coupling inductance L; as shown in Fig. 4.

In all of the circuits hereinbefore described, a potential is applied tothe parallel capacity 0,, which is approximately equal to the generatorpotential. However, it may happen that the condensers are constructedfor a much higher potential so that they cannot be fully utilized in theabovementioned circuits. In order to avoid this, the condenser C may beconnected with the generator 9 either indirectly through the agency oftransformers adapted to increase the potential or, preferably, acapacity C may be provided in the circuit through which the generatorcurrent passes. The condenser O and an inductance L, in the generatorcircuit may be so dimensioned that the potential of C will besufficiently high for eflicient operation. An embodiment of thisarrangement is shown in Fig. 5. The high potential at C, arises from thefact that, with respect to the basic wave of the generator, the circuitcomposed of L L 0,, and L C forms an inductive reactance, and the branchL 0 including the inductance of the generator forms a capacitivereactance. The same principle may be applied also to the other circuitarrangements.

Having described my invention, what I claim is:

1. A circuit arrangement for high frc quency sending stations comprisinga generator, an iron core choke coil and an 111- ductance coil connectedin series, a condenser connected in parallel with the gcnerator and inseries with the iron core choke coil and the inductance coil so as toprovide a loading branch circuit, an antenna coupled with said loadingbranch circuit and a tuning element separate from the condenser forpromoting the development of harmonics of the desired frequency in theloading branch circuit, said condenser serving also as a protection forthe generator against the harmonics.

2. A circuit arrangement for high frequency sending stations comprisinga generator, an iron core choke coil and an Inductance coil connected inseries, a condenser connected in parallel with the generator and inseries with the iron core choke coil and the inductance coil so as toprovide a loading branch circuit, an antenna. coupled with said loadingbranch circuit, and tuning means in the loading branch circuit forpromoting the development of a harmonic of the desired frequency in suchcircuit, said means being composed of an inductance coil and a condenserconnected in parallel with each other, the loading branch circuit beingtuned as a whole substantially to the desired harmonic.

3. A circuit arrangement for high frequency sending stations comprisinga generator, an iron core choke coil and an inductance coil connected inseries, a condenser connected in parallel with the generator and inseries with the iron core choke coil and the inductance coil so as toprovide a loading branch circuit, a tuning element separate from thecondenser for promoting the development of a harmonic of the desiredfrequency in the loading branch circuit, said element comprising aninductance coil and a condenser, and an antenna coupled with saidlast-mentioned coil.

A circuit arrangement for high frequency sending stat-ions comprising agen erator, an iron core choke coil and an inductance coil connected inseries, a trap connected in parallel with the generator and in serieswith the iron core choke coil and the inductance coil so as to provide aloading branch circuit, said trap having a capacitive reactance ofsuiiicient value to serve as a protection for the generator against allharmonics, and an antenna coupled with said loading branch circuit.

5. In combination, a source of alternating current, a circuit containinga frequency converter and coupled to said source, means connected inparallel to said circuit for protecting said source from the outputfrequency of said converter, said circuit having means for substantiallyresonating the output frequency of said converter, and means forutilizing said output frequency.

6. In combination, a source of alternating current, a first circuitcontaining a frequency converter and coupled to said source, a condenserconnected in parallel to said circuit for protecting said source againstthe output frequency of the converter, means for causing said source tooperate at substantially unity power factor, said means including atuning circuit comprising a condenser and inductance. in parallel insaid first circuit, said tuning circuit also causing the outputfrequency of said converter to be substantially resonated, and means forutilizing said output frequency.

MENDEL OSNOS,

